[Federal Register Volume 65, Number 197 (Wednesday, October 11, 2000)]
[Notices]
[Pages 60437-60439]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-25934]



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ENVIRONMENTAL PROTECTION AGENCY

[OPP-00679; FRL-6743-9]


Pesticides; Drinking Water Science Policies

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of availability.

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SUMMARY: EPA is soliciting comments on two draft pesticide science 
policy documents concerning pesticide risk assessment in drinking 
water. These documents are entitled, respectively, ``Drinking Water 
Screening-Level Assessments'' and ``Standard Operating Procedure (SOP) 
for Incorporating Screening-Level Estimates of Drinking Water Exposures 
into Aggregate Risk Assessments.'' Together, these documents describe 
EPA's approach to conducting a screening-level risk assessment of 
pesticide residues in water. This notice is one in a series of science 
policy documents related to the implementation of the Federal Food, 
Drug, and Cosmetic Act, as amended by the Food Quality Protection Act.

DATES: Comments, identified by docket control number OPP-00679, must be 
received on or before December 11, 2000.

ADDRESSES: Comments may be submitted by mail, electronically, or in 
person. Please follow the detailed instructions for each method as 
provided in Unit I. of the SUPPLEMENTARY INFORMATION. To ensure proper 
receipt by EPA, it is imperative that you identify docket control 
number OPP-00679 in the subject line on the first page of your 
response.

FOR FURTHER INFORMATION CONTACT: For ``Drinking Water Screening-Level 
Assessment,'' contact James Hetrick, Environmental Protection Agency 
(7507C), 1200 Pennsylvania, Ave., NW., Washington, DC 20460; telephone 
number: (703) 305-5237; fax number: (703) 308-6181; e-mail address: 
[email protected]. For ``Standard Operating Procedure (SOP) for 
Incorporating Screening-Level Estimates of Drinking Water Exposure into 
Aggregate Risk Assessments,'' contact Catherine Eiden, Environmental 
Protection Agency (7509C), 1200 Pennsylvania, Ave., NW., Washington, DC 
20460; telephone number: (703) 305-7887; fax number: (703) 308-5147; e-
mail address: [email protected].

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

     This action is directed to the public in general. This action may, 
however, be of interest to persons who produce or formulate pesticides, 
or who register pesticide products. Since other entities may also be 
interested, the Agency has not attempted to describe all the specific 
entities that may be affected by this action. If you have any questions 
regarding the applicability of this action to a particular entity, 
consult the person listed under FOR FURTHER INFORMATION CONTACT.

B. How Can I Get Additional Information, Including Copies of this 
Document and Other Related Documents?

    1. Electronically. You may obtain electronic copies of this 
document, and certain other related documents that might be available 
electronically, from the EPA Internet Home Page at http://www.epa.gov/. 
To access this document, on the Home Page select ``Laws and 
Regulations,'' ``Regulations and Proposed Rules,'' and then look up the 
entry for this document under the ``Federal Register--Environmental 
Documents.'' You can also go directly to the Federal Register listings 
at http://www.epa.gov/fedrgstr/.
    2. Fax-on-demand. You may request a faxed copy of the science 
policy documents, as well as supporting information, by using a 
faxphone to call (202) 401-0527. Select item 6083 for the document 
entitled ``Drinking Water Screening-Level Assessments'' and select item 
6084 for the document entitled ``Standard Operating Procedure (SOP) for 
Incorporating Screening-Level Estimates of Drinking Water Exposures 
into Aggregate Risk Assessments.'' You may also follow the automated 
menu.
    3. In person. The Agency has established an official record for 
this action under docket control number OPP-00679. The official record 
consists of the documents specifically referenced in this action, and 
other information related to this action, including any information 
claimed as Confidential Business Information (CBI). This official 
record includes the documents that are physically located in the 
docket, as well as the documents that are referenced in those 
documents. The public version of the official record does not include 
any information claimed as CBI. The public version of the official 
record, which includes printed, paper versions of any electronic 
comments submitted during an applicable comment period is available for 
inspection in the Public Information and Records Integrity Branch 
(PIRIB), Rm. 119, Crystal Mall #2, 1921 Jefferson Davis Hwy., 
Arlington, VA, from 8:30 a.m. to 4 p.m., Monday through Friday, 
excluding legal holidays. The PIRIB telephone number is (703) 305-5805.

C. How and to Whom Do I Submit Comments?

    You may submit comments through the mail, in person, or 
electronically. To ensure proper receipt by EPA, it is imperative that 
you identify docket control number OPP-00679 in the subject line on the 
first page of your response.
    1. By mail. Submit your comments to: Public Information and Records 
Integrity Branch (PIRIB), Information Resources and Services Division 
(7502C), Office of Pesticide Programs (OPP), Environmental Protection 
Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460.
    2. In person or by courier. Deliver your comments to: Public 
Information and Records Integrity Branch (PIRIB), Information Resources 
and Services Division (7502C), Office of Pesticide Programs (OPP), 
Environmental Protection Agency, Rm. 119, Crystal Mall #2, 1921 
Jefferson Davis Hwy., Arlington, VA. The PIRIB is open from 8:30 a.m. 
to 4 p.m., Monday through Friday, excluding legal holidays. The PIRIB 
telephone number is (703) 305-5805.
    3. Electronically. You may submit your comments electronically by 
e-mail to: [email protected], or you can submit a computer disk as 
described in this unit. Do not submit any information electronically 
that you consider to be CBI.. Electronic comments must be submitted as 
an ASCII file avoiding use of special characters and any form of 
encryption. Comments and data will also be accepted on standard disks 
in WordPerfect 6.1/8.0 or ASCII file format. All comments in electronic 
form must be identified by docket control number OPP-00679. Electronic 
comments may also be filed online at many Federal Depository Libraries.

D. How Should I Handle CBI that I Want to Submit to the Agency?

    Do not submit any information electronically that you consider to 
be CBI. You may claim information that you submit to EPA in response to 
this document as CBI by marking any part or all of that information as 
CBI. Information so marked will not be disclosed except in accordance 
with procedures set forth in 40 CFR part 2. In addition to one complete 
version of the comment that includes any information claimed as CBI, a 
copy of

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the comment that does not contain the information claimed as CBI must 
be submitted for inclusion in the public version of the official 
record. Information not marked confidential will be included in the 
public version of the official record without prior notice. If you have 
any questions about CBI or the procedures for claiming CBI, please 
consult the person listed under FOR FURTHER INFORMATION CONTACT.

E. What Should I Consider as I Prepare My Comments for EPA?

    You may find the following suggestions helpful for preparing your 
comments:
    1. Explain your views as clearly as possible.
    2. Describe any assumptions that you used.
    3. Provide copies of any technical information and/or data you used 
that support your views.
    4. If you estimate potential burden or costs, explain how you 
arrived at the estimate that you provide.
    5. Provide specific examples to illustrate your concerns.
    6. Offer alternative ways to improve the documents.
    7. Make sure to submit your comments by the deadline in this 
document.
    8. At the beginning of your comments (e.g., as part of the 
``Subject'' heading), be sure to properly identify the document you are 
commenting on. To ensure proper receipt by EPA, it is imperative that 
you identify docket control number OPP-00679 in the subject line on the 
first page of your response. You may also provide the name, date, and 
Federal Register citation.

II. Background Information

    On August 3, 1996, the Food Quality Protection Act of 1996 (FQPA) 
was signed into law. The FQPA significantly amended the Federal 
Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Federal 
Food, Drug, and Cosmetic Act (FFDCA). Among other changes, FQPA 
established a stringent health-based standard (``a reasonable certainty 
of no harm'') for pesticide residues in foods to assure protection from 
unacceptable pesticide exposure and strengthened health protections for 
infants and children from pesticide risks.
    Thereafter, the Agency established the Food Safety Advisory 
Committee (FSAC) as a subcommittee of the National Advisory Council for 
Environmental Policy and Technology (NACEPT) to assist in soliciting 
input from stakeholders and to provide input to EPA on the broad policy 
choices facing the Agency and on strategic direction for the Office of 
Pesticide Programs (OPP). The Agency has used the interim approaches 
developed through discussions with FSAC to make regulatory decisions 
that meet the new FFDCA standard, but that could be revisited if 
additional information became available or as the science evolved. In 
addition, the Agency seeks independent review and public participation, 
generally through presentation of the science policy issues to the 
FIFRA Scientific Advisory Panel (SAP), a group of independent, outside 
experts who provide peer review and scientific advice to OPP.
    During 1998 and 1999, as directed by Vice President Albert Gore, 
EPA and the U.S. Department of Agriculture (USDA) established a second 
subcommittee of NACEPT, the Tolerance Reassessment Advisory Committee 
(TRAC) to address FFDCA issues and implementation. TRAC comprised more 
than 50 representatives of affected user, producer, consumer, public 
health, environmental, states, and other interested groups. The TRAC 
met from May 27, 1998 through April 29, 1999.
    In order to continue the constructive discussions about FFDCA, EPA 
and USDA have established, under the auspices of NACEPT, the Committee 
to Advise on Reassessment and Transition (CARAT). The CARAT provides a 
forum for a broad spectrum of stakeholders to consult with and advise 
the Agency and the Secretary of Agriculture on pest and pesticide 
management transition issues related to the tolerance reassessment 
process. The CARAT is intended to further the valuable work initiated 
by the FSAC and TRAC toward the use of sound science and greater 
transparency in regulatory decisionmaking, increased stakeholder 
participation, and reasonable transition strategies that reduce risks 
without jeopardizing American agriculture and farm communities. The 
CARAT held its first meeting on June 23, 2000.
    As a result of the 1998 and 1999 TRAC process, EPA decided that the 
implementation process and related policies would benefit from 
providing notice and comment on major science policy issues. The TRAC 
identified nine science policy areas it believed were key to 
implementation of tolerance reassessment. EPA agreed to provide one or 
more documents for comment on each of the nine issues by announcing 
their availability in the Federal Register. In a notice published in 
the Federal Register of October 29, 1998 (63 FR 58038) (FRL-6041-5), 
EPA described its intended approach. Since then, EPA has been issuing a 
series of draft documents concerning the nine science policy issues. 
This notice announces the availability of two draft science policy 
documents concerning the methodology and standard operating procedures 
for conducting screening-level drinking water assessments.

III. Summary of Drinking Water Documents

A. Part A: ``Guidance for Use of the Index Reservoir in Drinking Water 
Exposure Assessments''

    The purpose of this draft science policy document is to provide 
guidance on using the index reservoir scenario for use in estimating 
the exposure in drinking water derived from vulnerable surfacewater 
supplies. Since 1996, the Agency has been using a standard small ``farm 
pond'' as an interim scenario for estimating a potential upper bound on 
drinking water exposure until more appropriate tools could be 
developed. The index reservoir is being implemented in conjunction with 
the percent cropped area factor to replace the farm pond scenario. 
These two steps are intended to improve the quality and accuracy of 
OPP's modeling of high-end drinking water exposure for pesticides.
    The index reservoir is intended as a replacement for the farm pond 
for use in drinking water exposure modeling. It is used in a similar 
manner to the farm pond except that flow rates have been calibrated for 
local weather conditions. Instructions for using the index reservoir 
are provided in this guidance document. The Exposure Analysis Modeling 
System (EXAMS) parameters for the standard index reservoir are provided 
in Appendix C of this guidance document.

B. Part B: ``Applying a Percent Crop Area Adjustment to Tier 2 Surface 
Water Model Estimates for Pesticide Drinking Water Exposure 
Assessments''

    The current process for screening food-use pesticides for drinking 
water exposure concerns from runoff to surface water is to run the 
Generic Estimated Environmental Concentrations (GENEEC, the Tier 1 
screening model) and compare the resulting concentration to the 
Drinking Water Level of Comparison (DWLOC). If the Tier 1 estimates 
exceed the DWLOC, then the Pesticide Root Zone Model/Exposure Analysis 
Modeling System (PRZM/EXAMS, the Tier 2 screening model) is run. When 
running PRZM/EXAMS for drinking water assessments, the current policy 
is to select the crop use which is expected to result in the

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highest runoff potential (based on application rate and method and on 
crop location). With issuance of this guidance document, OPP is 
changing its Tier 2 assessment process to incorporate the Percent Crop 
Area (PCA) concept.
    The PCA is a generic watershed-based adjustment factor which will 
be applied to pesticide concentrations estimated for the surface water 
component of the drinking water exposure assessment using PRZM/EXAMS 
with the index reservoir scenario. The output generated by the PRZM/
EXAMS model is multiplied by the maximum PCA (expressed as a decimal) 
generated for the crop or crops of interest. For purposes of conducting 
the Tier 2 drinking water assessment, the crop of interest would most 
typically be the labeled crop use that is anticipated to result in the 
greatest mass of pesticide entering the surface water body via runoff. 
Currently, OPP will apply PCA adjustments for four major crops--corn, 
soybeans, wheat, and cotton. For pesticides applied to corn, soybeans, 
wheat, and cotton, Tier 2 drinking water exposure assessments should 
utilize the appropriate index reservoir scenario and corresponding 
PCA(s).
    This guidance results from a May 1999 presentation to the FIFRA 
SAP, ``Proposed Methods For Determining Watershed-derived Percent Crop 
Areas And Considerations For Applying Crop Area Adjustments to Surface 
Water Screening Models,'' and the response and recommendations from the 
panel. A more thorough discussion of this method and comparisons of 
monitoring and modeling results for selected pesticide/crop/site 
combinations is located at http://www.epa.gov/scipoly/SAP/1999/may/
pca--sap.pdf. The SAP did not provide guidance in a few 
critical areas, such as defining ``major'' versus ``minor'' uses or 
what to do in most cases where a pesticide is used on multiple crops.
    This draft science policy document provides guidance on when and 
how to apply the PCA to model estimates, describes the methods used to 
derive the PCA, and discusses some of the assumptions and limitations 
with the process.

IV. Summary of ``Standard Operating Procedure (SOP) for 
Incorporating Screening-level Estimates of Drinking Water Exposure 
into Aggregate Risk Assessments''

    This draft science policy document is the SOP for a document 
entitled, ``Estimating the Drinking Water Component of a Dietary 
Exposure Assessment'' (notice of availability published in the Federal 
Register of November 10, 1999, 64 FR 61346; FRL-6389-7). It outlines 
the general approach to incorporating screening-level estimates of 
drinking water exposure into OPP's human health aggregate risk 
assessments. Specifically, it provides:
    (1) A step-by-step process for OPP staff to follow while 
coordinating their work on registration and reregistration actions.
    (2) Terms, definitions, descriptions, and calculations for use in 
incorporating estimates of pesticide concentrations in surface water 
and groundwater from screening-level models into aggregate risk 
assessments.
    (3) Examples of specific language that may be used in health 
effects risk assessment documents to characterize screening-level 
exposure estimates for drinking water.
    (4) An appendix containing example scenarios and calculations.
    Under the procedures outlined in this draft science policy 
document, the resulting estimates of risk associated with a pesticide 
in drinking water are considered to be unrefined, high-end, upper-bound 
values. However, since many compounds can be ``cleared'' of drinking 
water concerns using these screening-level procedures, the process 
saves limited resources by providing an efficient means to determine 
whether a more refined assessment of drinking water exposure for a 
specific compound is warranted. This document is an updated version of 
the existing SOP for incorporating drinking water exposure into 
aggregate risk assessment and replaces the previous SOP dated August 1, 
1999 (HED SOP 99.5, 1999).

V. Questions/Issues for the Drinking Water Screening-Level 
Assessment and SOP Documents

A. Index Reservoir (Part A)

    1. Is the index reservoir a suitable replacement for the standard 
farm pond for screening-level drinking water assessments?
    2. Do the process and criteria used to select the index reservoir 
represent a reasonable approach? Are there any other criteria the 
Agency should consider when we reassess the reservoir scenario in the 
future?
    3. There are many refinements to the reservoir approach and its 
screening approach in general. Which of these refinements should have 
the highest priority?
    4. It is assumed that there is no spray drift buffer zone around 
the perimeter of the reservoir. Are there any suggestions on how to 
develop a standard spray drift buffer zone for the index reservoir?

B. Percent Cropped Area (Part B)

    1. The PRZM runoff model in the index reservoir may be limited to 
watersheds of no more than 20 square miles. Are there any suggestions 
in addressing the scale limitation of the PRZM model?
    2. Is it reasonable to use a PCA adjustment to PRZM/EXAMS modeling 
for more accurate and appropriately conservative estimates of pesticide 
concentrations in surface water for screening evaluations of drinking 
water exposure?
    3. Is the GIS procedure for calculating PCA appropriate for 
accounting for the portion of the watershed planted to the crops or 
crops of interest?
    4. A default PCA has been calculated for cases where a defensible 
PCA cannot be calculated. Is it appropriate to use a default PCA?

C. The Standard Operating Procedure

    Given the limited information available on pesticides in drinking 
water, is the approach outlined in the SOP guidance document a 
reasonable way to incorporate the available information on pesticide 
concentration in surface and ground water from screening-level models 
into aggregate human health risk assessment?

VI. Policies Not Rules

    The policy document discussed in this notice is intended to provide 
guidance to EPA personnel and decision-makers, and to the public. As a 
guidance document and not a rule, the policy in this guidance is not 
binding on either EPA or any outside parties. Although this guidance 
provides a starting point for EPA risk assessments, EPA will depart 
from its policy where the facts or circumstances warrant. In such 
cases, EPA will explain why a different course was taken. Similarly, 
outside parties remain free to assert that a policy is not appropriate 
for a specific pesticide or that the circumstances surrounding a 
specific risk assessment demonstrate that a policy should not be 
applied.

List of Subjects

    Environmental protection, Administrative practice and procedure, 
Agricultural commodities, Pesticides and pests.


    Dated: September 27, 2000.
Susan H. Wayland,
Acting Assistant Administrator for Prevention, Pesticides and Toxic 
Substances.

[FR Doc. 00-25934 Filed 10-10-00 8:45 am]
BILLING CODE 6560-50-S